The demand for compact and miniature heat exchangers in refrigeration equipment has led to the development of new heat transfer enhancement technologies. Twisted tape inserts are cheap and easy to manufacture

and can be classified as a passive heat transfer enhancement technology. They have great application potential in the evaporator of refrigeration systems. Inserting twisted tapes into a tube with two-phase flow boiling can increase the surface coefficient of heat transfer and pressure drop in the tube. The analysis in this study revealed that changes in mass flow and vapor quality positively correlated with the the surface coefficient of heat transfer and pressure drop

while changes in pipe diameter

twist ratio

and saturation temperature negatively correlated with the surface coefficient of heat transfer and pressure drop. The complexity of the boiling heat transfer process

different evaluation criteria

and limited experimental conditions are the main reasons why the best conditions for twisted tape insertions are inconsistent as explained by different scholars. In addition

this study also summarized the correlations for the surface coefficient of heat transfer and pressure drop of boiling heat transfer in tubes with twisted tape inserts as explained by different researchers. Finally

we believe that the best operating conditions of the twisted tape inserts need to be further clarified

and the twisted tape insert needs to be studied in real evaporators or inverter compressors.